1. Field of the Invention
With general infrastructure within the US and around the world in a precarious state of decay it has been the object of many to provide for a cost effective method to perform in situ-rehabilitation of these properties. In the industrial sector, pipe and transmission lines carrying volatile and dangerous or hazardous materials are constantly at risk of failure due to age, neglect or lack of funds to replace or repair with traditional methods. In the global municipal arena, waste collection and water distribution systems are seriously compromised with failures creating community disturbances, commercial loss and environmental incidents. The US EPA Clean Water Act of 1989 outlines mandatory restrictions and covenants imposed on municipalities to improve the conditions of their water and wastewater systems. The EPA Conference of Mayors report of 2007 surveyed 1500 US Cities' infrastructure needs resulting in $15B in needed repairs and upgrades. The RSCA has also increased scrutiny on chemical processing facilities, petrochemical facilities and pipeline transmission calling for proactive inspection and repair of millions of miles of pipe, conduit and passageway.
The conventional lining materials and methods have undesirable environmental impacts, e.g., leaching of styrene's, CFC's, VOC's and endocrine disruptors into the effluent. Effects of endocrine disruptors are believed to include growth defects and may result from relatively minor exposure to chemicals.
An additional undesirable impact results from the annulus created between the interior pipe wall and the liner. This annulus not only propagates infiltration but also exfiltration—the toxic effluents going back into the surrounding ground, ground water, lakes, streams and aquifers. The conventional resins are thermosetting resin. These resins shrink causing an annulus to form between the pipe wall and the liner. This annulus permits infiltration of ground water into the pipeline flow as well as pipeline effluent into the soil and ground water.
Generally the only reason that customers have their pipes rehabilitated is due to erosion, corrosion, cracks and leaking joints. In a method that leaves an annular space, the method only allows for the exfiltration in the future. The way this happens is that in the initial installation, the annular space between the method and the manhole or vault is sealed with mortar or some other material. At that time (after repair) it will pass a hydrostatic test but as age, corrosion, erosion and the constant pressure continue from infiltration at the manhole will work on the seal, causing the seal to begin to leak. The infiltration then gets into the effluent that is flowing through the manhole. Likewise the material flowing through the manhole can get into the annular space finding cracks and open joints therefore exfiltrating to the surrounding soils and water table around the pipe.
Footprint as defined in this disclosure would be that the other rehabilitation methods are required to have their vehicles and equipment right at the manhole/pipe access to facilitate their repair process. Due to access often times being in yards, medians, fields, woods, creeks, etc., the vehicles tear up soils, grass, remove trees, etc. Most often these methods have to excavate the manhole or vault to facilitate inserting their liners. Often times in creek or drainage culverts the contractors have to put their equipment directly in the water thereby leaking oils, fuels, etc. into the water. Also in these applications, the thermosetting resin leaches into the rivers, creeks, lakes, ponds, killing fish and organisms etc., due to inflation of the “bag” or “sock” with hot water or steam. Additionally with cured in place, (hereinafter “CIPP”) and use of high density polyethylene (hereinafter “HDPE”) used in slip lining, the pipe capacity is downsized so much that the rehabilitated (narrowed) pipe increases flow velocities. This results in creek scour that causes loss of stream banks, plant life and animal life. Additionally in these applications with the water infiltrating into the annular space through joints and cracks, the infiltrating water beings surrounding soils with it. In time this results in a large voids around the pipe and causing the formation of sink holes (economic as well as environmental) in roads and yards caused by soils getting into the pipe.
The method of the present invention does not create an impact of leaching CFC's, VOC's, or endocrine disrupters being emitted into air, water and effluent and the method does not cause a footprint due to the use of an umbilical allowing equipment to be as much as 400 feet or more from the access point of the pipe. The umbilical can traverse unlimited times around buildings, trees, etc via the use of roller quadrants. Contractors using the apparatus or method of the invention do not have to dig up or disrupt access paths as the umbilical is only 2″ in diameter and can be inserted into any access.
The present invention generally relates to apparatus and methods for applying a liner to the interior surfaces of pipes, conduits and passageways. The disclosure also more specifically speaks about the ability to remotely apply a consistent and continuous lining in a pipe. The liner is inert after application and does not contain and/or leach volatile organic compounds (VOC's) or chlorofluorocarbons “CFC” or hydro fluorocarbons “HCFC's” or endocrine disruptors.
2. Description of Related Art
Prior art demonstrates numerous methods to rehabilitate pipelines, conduits and passageways from the inside in order to restore asset integrity.
In situ repair methods incorporating a resin impregnated fiber lining tube are described by Wood et al, U.S. Pat. No. 5,409,561 and Kliest, U.S. Pat. No. 6,427,726. In these cured-in-place (CIPP) methods, conventional resins include polyester, vinyl ester and even epoxy resin form a matrix with a tubular textile material, positioned within the deteriorated pipe section, are forced into intimate contact with the pipe interior surface and allowed to cure. The cure time may be hours or days. There are many instances and conditions where the above methods are either not practical or are unsuitable.
Davis U.S. Pat. No. 6,986,813 describes utilizing a polymer product that is sprayed onto the interior pipe walls to form a seamed monolithic liner. A seamed monolithic liner is created by the inability of the lining method or apparatus to continuously line a section of pipe. As a result there are stop points in the lining and replacement lining overlaps the previously applied liner, thereby causing a seam. This patent attempts to overcome many problems identified in prior art. Typical, prior art spray in type liners experience major problems as evidenced in the plugging of spray tips, slow curing coatings resulting in surface sags and inconsistent material application thickness and other constraints resulting in finished liner thicknesses in the 0.200-0.400 inch range, rendering them unsuitable for many applications.
Davis attempts to overcome the first constraint of spray tip plugging by incorporating a blow off mechanism attached to the tip of the spray gun in an effort to eliminate plugging during operation. Additionally, Davis purports to employ a fast setting material to eliminate sags. The combination of these two assumed improvements actually result in a compounded problem. The Davis patent teaches continuous blowing of air through the time of the spray gun as a method to prevent clogging. Unfortunately adding air flow to the product stream only increases the atomization of the spray resulting in higher static attraction to moving parts. Purging the spray tip with compressed air does not eliminate the plugging problem. A splatter shield is also mentioned to deflect errant spray material from occluding the spray orifice. In practical operation, the root cause of the repeated clogging of the spray tip is more a function of design.
In Davis, a spinning flat or slightly obliquely angled disc is used to propel the projected fast setting lining material onto the pipe walls. This flat or slightly obliquely angled spinning disc design as it relates to the direct right angle diffusion of the spray causes a significant amount of rebounding/ricochet lining material to accumulate on the splatter shield and air blow off mechanism, ultimately resulting in total blockage of the tip and other crucial mechanical functions within a short period of time. This does not allow for continuous operation or lining of more than 10-20 feet of pipe without the need to retract the apparatus and clean.
The spinning disc design of Davis fails to satisfy the requirement for a uniform lining thickness as well. As described, the resultant physics do not afford equal dissipation of lining material in the full 360 degrees of circumference. As the fast setting material is projected at the spinning disc at a generally perpendicular angle, the high speed of the spinning disc induces a disproportionate amount of material to the first 90 degree arc that is quickly thrown to the pipe walls. The current apparatus due to its flat or slightly oblique design does not afford the coating material any dwell time to equalize mass and distribute the coating material around the circumference of the disc prior to being ejected. This ultimately results in thicker coating or lining in the first 180 degrees of circumferential arc of the pipe wall. This presents an unacceptable condition when uniformity is necessary to calculate ultimate liner properties and performance which is required by end users.
Static Build Up:
There is no consideration in prior art for the disruption caused by static build up.
Static build up is caused by the high rpm's of the shaft and disc as they relate to close proximity to pipe wall and the inherent need due to lining cure. Forced air is not a cure for static build up. Static build up is controlled through high pressure and high heat impingement of the lining components only. The forced dry air is to keep the pipe surface as dry as possible and to keep product mist from coating camera lenses as well as to force dry air to assure a dry working environment for the apparatus.
Static build up in prior art is compounded by the fact that the apparatus uses a “spray” pattern to send material from the tip to the spinner disc. This spray naturally causes atomization of the lining material which results in more static charge and also makes it easier for the static attraction of the shaft and disc to “pull” the material as it passes by these parts.
This static attraction between coating materials and the shaft/disc result in material stalactites and stalagmites depending on their positional relationship to these devices.
These formations will in time severely impede if not halt the apparatus' ability to continually line the pipe.
The build up of these formations will divert the flow from the tip to the spinner disc resulting in additional disproportionate distribution of coating material to the pipe wall.
Formations continue to grow as the lining process proceeds.
Formations eventually break off due to their increased weight and centrifugal force being applied.
Formations that get imbedded in the uncured liner causing profiles in the flow channel that will result in diminished flow capacity of the liner due to increased coefficient of friction. Also the imbedded pieces causes “snag” areas in mixed effluent pipelines such as sewage which results in solids—toilet paper etc—getting caught on them and building up sometimes to block pipeline flow.
Formations that are imbedded in the in the first few oscillation strokes of the apparatus end up diverting or blocking the coating material from ever reaching the pipe wall due to the straight projection off the spinner disc. This creates through voids in the finished liner.
This situation results in the need to remove the prior art apparatus from the pipe and clean many times to actually complete a full liner application hence diminishing the claims of a faster method in prior art.
Spinner Disc Build Up:
Current art has an inherent design that has no way of stopping the build up of coating material on the spinner disc.
In prior art the spinner disc is subject to a “spray” formation from the tip.
Utilizing a spray pattern creates a “dry fall” effect at the point the coating hits the spinner disc. This does not allow the disc to totally disperse the lining material as the material does not have the weight and mass needed to completely propel off the disc effectively. It does not have the wet out capabilities of a tightly uniform stream of lining material as taught by the instant disclosure.
In prior art, spray is immediately propelled from tip at a set pressure which in turn slows the rpm of the spinner disc due to direct force applied by the sprayed coating material velocity. The initial required rpm is then never fully achieved. The spinner motor from this point on is trying to regain the initial rpm with failure.
A standard pneumatic motor is used in the prior art. The pneumatic motor produces high rpm's and low torque. Air motors have been found to be a necessity as electric motors with high rpm/high torque are too large for the apparatus in small diameter pipe. Hydraulic units work but the need to supply hydraulic pressure at 500 feet requires bulking up the umbilical with hoses, adding costly pumps and additional weight and diameter to the umbilical.
The above mentioned “dry fall” effect starts to gradually slow the rpm of the spinner disc due to the weight of the resulting build up. As the rpm slows due to low torque, the effect becomes greater and greater having a “snowball” effect on the apparatus, completely stopping the spinner disc and ultimately rendering the apparatus incapacitated in as little as 10 minutes.
This results in lining material still being projected from the tip without being dispersed by the disc. The material then drips to the bottom of the pipe resulting in piles of lining only on the bottom of the pipe.
This results in the need to constantly remove the apparatus from the pipe and clean the shaft and disc which can take hours then reinserting to once again line for a short amount of time. This is a constant procedure with prior art. This consistent required retraction and insertion can result in inter-coat de-lamination of the liner due to possible contamination of the already installed liner while the retraction process and cleaning process is being completed.
In prior art it is stated that the apparatus can line for hours and from intervals of 300-600 feet. This, however, is not possible in a single insertion and retraction cycle. This adds considerable time to the process evacuating any advantage in time or economics over other lining methods as stated in prior art.
Trajectory Geometry:
Prior art utilizes a flat or maximum oblique angle in its spinner disc. This design results in a straight stream of dissipation off the spinner disc.
Prior art uses relatively slow oscillation of the spinner disc rod with long smooth linear strokes to overlap material to prevent sags and runs. This remains a tight straight dissipation stream off the disc throughout the oscillation cycle.
The apparatus only coats in one direction in the pipe to complete the coating.
All pipe has a natural profile whether it be at bell/spigot joints, welds, tuberculation etc.
The prior art does not have the ability due to its design, mechanics and straight or right angle stream to completely line the forward or backward edge of these profiles as it relates to the position of the apparatus. The forward side of these profiles do not get coated and therefore there are exposed areas in the existing pipe wall.
Prior art also does not have the ability to reverse the rotation on the spinner disc. There are many times in pipe where there will be a lateral intrusion—a small pipe sticking into the main pipe—the maximum penetration is usually ¾″. In this instance there is no way that lining can be placed on the underside of this intrusion pipe or any profile for that matter without counter rotation. The apparatus of the instant invention has the ability to counter rotate either through transfer or air from exhaust to intake and reverse. More typically this is done through electronically switched bi-directional transmission or transfer case that is in between the shaft and the air motor collet. The reason for this is that on high rpm air motors they easily wear out if they are run in both directions. Compounding this problem in the prior art is that the unit does not have the ability to start and stop flow. Flow must be stopped while the motor is being reversed in rotation.
Multiple Starts and Stops:
Prior art design and mechanics do not allow to open and close the valving rod or spray tip stopper more than one open and close cycle. The prior art uses a spray tip orifice that is machined so that the valving rod seats inside it. When this is open, spray comes through the orifice. It is then closed and residual mix material encapsulates this area and basically locks it into that position. The prior art mechanics does not have the pull force or the ability to have a momentum surge on the valving rod to break this free—hence the valving rod cannot be remotely opened up more than one cycle—open/close—done. The present invention apparatus uses a different sealing method at the interface of the termination rod (valving rod in prior art) end and the stream orifice to seal—mixed product encapsulation of the area is made to be a minimum through this design. The instant invention also has a different design of the termination rod actuator—it has a much higher pull force coupled with a function that allows for some “free” pull force momentum to build prior to actuating the termination rod. This allows the rod to brake free therefore allowing unlimited open and close cycles.
Regarding the prior art, in the event that there is a malfunction in control systems or an impediment of the umbilical retraction which is common, the apparatus must be disengaged from continuing to spray. If not the result is heavy rings in the liner. If this event happens the apparatus must be retracted from the pipe and the impingement block completely disassembled, cleaned, reassembled and re inserted into pipe. This is a very time consuming process. This design and mechanical flaw also does not allow the apparatus to complete sleeve or individual repairs in the pipe unless you do them one at a time due to the necessity to clean after every valving rod cycle.
Dimensional Restrictions on Insertion and Retraction:
Equipment of the prior art, due to its overall length, cannot be inserted or retracted from an underground pipe with the access being a manhole or vault with a diameter or horizontal dimension or less than 5 feet.
This overall dimension is the direct result of the claims for the method/mechanics of oscillation to afford slow dissipation and overlapping of the lining material.
Additionally the 23″ bend radius and mechanics of the attachment bracketing of the prior art umbilical is such that it significantly increases the overall dimension of this apparatus.
Typically in the private sector and in the municipal market sectors all underground pipes are only accessible through the above mentioned accesses. Rarely is there excavation afforded to allow insertion of apparatus into the pipe. The prior art apparatus can be disassembled then reassembled as it is being inserted in the pipe. This is a very time consuming process. This, however, does not afford this apparatus the ability to coat the entire pipe. The unit must stop lining to be disassembled on retraction. This stoppage must occur in manholes and vaults with a diameter of horizontal dimension of less than five feet. This results in as much as 16″-30″ of pipe not being coated in a typical manhole or vault. There is currently no acceptable way afterward to line this section that is void of lining material. Prior art creates a void or in the pipe lining for the pipe not the manhole. Due to its length from the oscillation stroke, the umbilical bend radius and equipment design, the prior art lining equipment has to be stopped in a 4′ manhole with 30′ of the robot still inside the pipe. At this point all lining processes must be stopped. There is no way after this in a small diameter pipe to get in and manually line the pipe section that was missed.
Due to the design and mechanics of the prior art, it cannot line vertical pipe or pipe with a slope of more than 30 degrees.
Diameter:
Due to the design and mechanics of the prior art, it cannot be utilized in a pipe with a diameter of less than 10″. Prior art states that it can be used in 6″ pipe. The basic dimensions however do not allow for this as filed in the drawings. This is evident to a person skilled in the art after examination of the detailed description of the equipment in Davis U.S. Pat. No. 6,986,813 discussed above. Review of the description and drawings demonstrate it would be impossible to be short enough or narrow enough to fit into a 6″ pipe.
Over and above the fact that the unit's dimensions restrict its ability to line pipe with diameters less than 10″, its function of mechanics also severally impedes this ability. The unit utilizes oscillation. This results in all oscillating parts to be on the exterior of the apparatus and in close proximity to the pipe wall. No matter how long the determined length of that oscillation may be (5″-36″) the entire length and width of the carriage or shuttle plate is moving. Pursuant to prior art drawings this length is longer that the length of the base assembly when the spray head is considered. Example: if the oscillation is set for 10″, the entire length of the unit is moving 10″ on every stroke exposing the entire length to profile or offsets. The full width and length of the upper apparatus shuttle plate is in motion. The apparatus as designed also has many right angle projections that can get caught on joints and or profiles in pipe wall.
Additionally due to the apparatus design and mechanics as it relates to external part oscillation it is very easy for it to get “hung up” in small diameter pipe. All pipe systems have profiles, sags and offsets. When the current apparatus encounters these obstructions it will stop the oscillation process. This may only be momentary or for extended lengths of time. In either case it causes a build up or “ringing” in the new coating which is unacceptable. If the stoppage of oscillation occurs for an extended length of time it can actually close off the pipe entirely with lining material and/or lock the apparatus in the pipe.
The external oscillation parts are all on the exterior of the unit. This exposes them to all the overspray and existing contaminants that are in the pipe while being coated. This eventually impedes their function resulting in diminished capabilities or incapacitation.